Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D13/00—Electrophoretic coating characterised by the process
  • C25D13/12—Electrophoretic coating characterised by the process characterised by the article coated
  • C25D13/14—Tubes; Rings; Hollow bodies
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/44—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications
  • C09D5/4488—Cathodic paints
  • C09D5/4492—Cathodic paints containing special additives, e.g. grinding agents

Definitions

• the invention relates to a process for the preparation of preparations containing bismuth salts, bismuth oxide being reacted in a specific manner with lactic acid and then the mixture of bismuth lactate and bismuth lactate obtained being dispersed in a paint binder, and the use of these preparations as a catalyst component in cathodic electrodeposition paints.
• the bismuth salts are obtained by the reaction of 1.0 mol of bismuth oxide with 7.0 mol of the respective hydroxycarboxylic acid, the excess of 1.0 mol of acid being intended to ensure the most quantitative possible conversion.
• Deionized water and the acid are introduced and, at 70 ° C., commercial bismuth oxide (Bi 2 O 3 ) is added in portions with stirring.
• the precipitate is filtered off and dried at a temperature of 40 to 60 ° C.
• the catalyst-containing paint binders are prepared in such a way that before the addition Add substantial amounts of water as a diluent to the bismuth salt of the protonated binder solution and then homogenize the batch for several hours.
• the bismuth salt is homogenized in a paint binder that can be used as a paste resin on a dissolver and then on a bead mill, optionally in the presence of pigments.
• the isolated and dried bismuth salts tend to agglomerate during storage.
• a larger amount of acid is required for the "digestion" of the bismuth oxide than is subsequently required for the neutralization of the entire paint binder. Excess acid is thus introduced into the immersion lacquer, which noticeably increases the power requirement during operation of the immersion pool.
• the reaction mixture often forms a crystalline, sticky mass during the "digestion" which cannot be stirred or filtered.
• the invention further relates to the use of the preparations prepared according to the invention, optionally in the form of pigment pastes, in combination with cationic lacquer binders which can be crosslinked by transesterification and / or transamidation and / or transurethaneization and / or by reaction of terminal double bonds, these being identical to or different from that in of the preparation contained paint binders and are optionally present as dispersions for the formulation of cathodically depositable electrodeposition paints with the proviso that they contain a bismuth content, based on the solids content of the total paint binder, of 0.5 to 3.0% by weight, preferably from 0.8 to 2.5% by weight.
• the invention relates to cathodically depositable electrodeposition paints with a bismuth content, based on the solids content of the entire paint binder, of 0.5 to 3.0% by weight, preferably 0.8 to 2.5% by weight, which the Preparations prepared according to the invention, optionally in the form of pigment pastes, and also more terminally by transesterification and / or transamidation and / or transurethanization and / or by reaction Double bonds contain crosslinkable cationic paint binders, these being identical to or different from the paint binder contained in the preparation and optionally being in the form of dispersions.
• the claimed process is technologically simple and can be reproduced excellently even with large batches.
• the electrodeposition varnishes that can be deposited cathodically have excellent application and film properties.
• the use of lead and tin compounds as catalysts can be dispensed with.
• the preparations are produced in the procedure defined in the main claim. After the reaction steps Aa) to Ac), the mixture of bismuth lactate and bismuth lactate is combined with a cationic paint binder. It is advantageous if the preparations have a viscosity in the range from 4000 to 10000 mPa.s / 23 °. They are therefore flowable and easy to manipulate even at room temperature.
• cationic paint binders are selected for the preparations as are used as "base resins" for the production of the cathodically depositable electrocoat materials, but without hardener component and not as a dispersion.
• lacquer binders which can be crosslinked by transesterification and / or transamidation and / or transurethanization and / or by reaction of terminal double bonds are known from the literature. It is therefore not necessary to go into detail about the structure and chemistry of these products.
• reaction step (B) If the preparations are processed further in the form of pigment pastes, it is advantageous to use special pigment paste resins in reaction step (B), as described, for example, in DE 2634211 C2, DE-OS-2634229, EP 107088 A1, EP 107089 A1, EP 107098 A1, EP 251772 A2, EP 336599 A2, AT-PS 380 264 and AT-PS 394372.
• the electrodeposition lacquers which can be deposited cathodically have very good storage stability even over a relatively long period of time. H. neither sediment formation nor a decrease in reactivity.
• the properties of the deposited wet films or the crosslinked paint films fully correspond to the very high quality standard required by the automotive industry.
• the bismuth salts containing preparations CAT 1 to CAT 4 are prepared from the products in table 1 in the appropriate proportions:
• VEW and lactic acid I (2.0 mol) are placed in a suitable reaction vessel with a stirrer.
• Bismuth oxide (1.0 mol) is added in portions with stirring. The mixture is homogenized for 30 to 60 minutes, the temperature rising to about 40 ° C.
• Lactic acid II (1.0 mol) is then added. The mixture is again homogenized for 30 to 60 minutes.
• 190 g of a bisphenol A epoxy resin (EEW approx. 190) and 1425 g of a bisphenol A epoxy resin (EEW approx. 475) are dissolved in 597 g EGL at 100 ° C.
• the solution is cooled to 60 ° C. and 126 g of diethanolamine are added.
• the temperature is slowly increased to 80 ° C. over 2 hours.
• 169 g DEAPA are added.
• the temperature is raised to 120 ° C. in 2 hours.
• 478 g of CE are added, the mixture is stirred for 5 hours at 130 ° C. and finally diluted with EGL to a solids content of 65% by weight.
• the resin has an amine number of 91 mg KOH / g and a hydroxyl number of 265 mg KOH / g, each based on the solid.
• a homogeneous solution of 16 g of diisopropanolamine in 20 g of BUGL is then rapidly added to the reaction mass at 85 ° C., the batch is stirred for a further 2 hours at 90 ° C. and finally the product at 90 ° C. with 13 g EGL and at 40 ° C. with Diluted acetone.
• the resin has a solids content of 57% by weight, an amine number of 58 mg KOH / g and a hydroxyl number of 250 mg KOH / g, each based on the solids.
• the polymeric amine is prepared by reacting 1 mol of diethylenetriamine with 3.1 mol of 2-ethylhexylglycidyl ether and 0.5 mol of a bisphenol A epoxy resin (EEW approx. 190) in 80% MP solution.
• the product has a viscosity (DIN 53211/20 ° C; 100 g resin + 30 g MP) of 60 to 80 seconds.
• a reaction vessel which is equipped with a device suitable for the azeotropic process and with a bubble cap column for separating the alcohol component formed in the partial transesterification 29.7 g (0.9.) to a mixture of 160 g (1 mol) of diethyl malonate, 0.34 g (0.004 mol) of piperidine and 0.22 g (0.004 mol) of formic acid at 80 ° C. Mol) PF 91 added in portions so that a temperature of 95 ° C is not exceeded when the exothermic reaction begins.
• the reaction mixture is stirred at 95 ° C until the PF 91 is completely dissolved.
• the temperature is raised to 110 ° C. in the course of 2 hours with the elimination of water. After reaching 110 ° C, a total of 9 g of water is distilled off with special gasoline (boiling range 80 - 120 ° C) as an entrainer. The entrainer used is then removed by applying a vacuum.
• the product obtained has a solids content of 80 ⁇ 2% by weight (30 minutes, 120 ° C.), a viscosity according to GARDNER-HOLD (10 g product + 2 g DGDME) of K and a refractive index n 20 / d of 1. 4960.
• the amounts of CAT 1 to CAT 4 corresponding to Table 2 are mixed into the batch either before grinding in the bead mill or the finished pigment paste.
• the paint batches are adjusted to a solids content of 18% with VEW.
• the paints are cathodically deposited on cleaned, non-phosphated steel sheets.
• the deposition conditions are chosen so that the films have a Have dry film thickness of 22 ⁇ 2 ⁇ m.
• Hardening is carried out by baking in a convection oven (20 min / 170 ° C).

Landscapes

• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Health & Medical Sciences (AREA)
• Molecular Biology (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Metallurgy (AREA)
• Paints Or Removers (AREA)
• Catalysts (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Applications Claiming Priority (3)

Publications (2)

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• 1993
  • 1993-09-07 AT AT0179493A patent/AT398987B/de not_active IP Right Cessation
• 1994
  • 1994-08-10 TW TW086117541A patent/TW474977B/zh active
  • 1994-09-02 RU RU96106899A patent/RU2137866C1/ru active
  • 1994-09-02 AU AU74848/94A patent/AU7484894A/en not_active Abandoned
  • 1994-09-02 KR KR1019960701147A patent/KR100340367B1/ko not_active IP Right Cessation
  • 1994-09-02 BR BR9407408A patent/BR9407408A/pt not_active IP Right Cessation
  • 1994-09-02 CN CN94193728A patent/CN1044140C/zh not_active Expired - Lifetime
  • 1994-09-02 EP EP94924630A patent/EP0717794B1/de not_active Expired - Lifetime
  • 1994-09-02 ES ES94924630T patent/ES2107244T3/es not_active Expired - Lifetime
  • 1994-09-02 CZ CZ96690A patent/CZ285838B6/cs not_active IP Right Cessation
  • 1994-09-02 AT AT94924630T patent/ATE156525T1/de not_active IP Right Cessation
  • 1994-09-02 DE DE59403675T patent/DE59403675D1/de not_active Expired - Lifetime
  • 1994-09-02 WO PCT/AT1994/000123 patent/WO1995007377A1/de active IP Right Grant
  • 1994-09-07 ZA ZA946894A patent/ZA946894B/xx unknown
• 1997
  • 1997-09-19 US US08/933,845 patent/US5936013A/en not_active Expired - Lifetime

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